From: mkl@pengutronix•de (Marc Kleine-Budde)
To: linux-arm-kernel@lists•infradead.org
Subject: DWord alignment on ARMv7
Date: Fri, 4 Mar 2016 12:19:32 +0100 [thread overview]
Message-ID: <56D96F44.6010905@pengutronix.de> (raw)
In-Reply-To: <CAKv+Gu8b05BsNMPD2QNf9pLyRwSNGhc-5TVskwfudYuVqeCoAw@mail.gmail.com>
On 03/04/2016 12:14 PM, Ard Biesheuvel wrote:
> I wonder if we should simply apply something like the patch below
> (untested): it depends on how many 32-bit architectures implement
The "Last line effect" hit here.
> double word load instructions, but for ones that don't, the patch
> shouldn't change anything, nor should it change anything for 64-bit
> architectures.
> -------8<-----------
> diff --git a/include/linux/unaligned/access_ok.h
> b/include/linux/unaligned/access_ok.h
> index 99c1b4d20b0f..019d0b7ea6a3 100644
> --- a/include/linux/unaligned/access_ok.h
> +++ b/include/linux/unaligned/access_ok.h
> @@ -16,7 +16,11 @@ static inline u32 get_unaligned_le32(const void *p)
>
> static inline u64 get_unaligned_le64(const void *p)
> {
> - return le64_to_cpup((__le64 *)p);
> + if (BITS_PER_LONG == 64)
> + return le64_to_cpup((__le64 *)p);
> + else
> + return ((u64)le32_to_cpup((__le32 *)p)) |
> + ((u64)le32_to_cpup((__le32 *)p + 1) << 32);
> }
>
> static inline u16 get_unaligned_be16(const void *p)
> @@ -31,7 +35,11 @@ static inline u32 get_unaligned_be32(const void *p)
>
> static inline u64 get_unaligned_be64(const void *p)
> {
> - return be64_to_cpup((__be64 *)p);
> + if (BITS_PER_LONG == 64)
> + return be64_to_cpup((__be64 *)p);
> + else
> + return ((u64)be32_to_cpup((__be32 *)p) << 32) |
> + ((u64)be32_to_cpup((__be32 *)p + 1));
> }
>
> static inline void put_unaligned_le16(u16 val, void *p)
> @@ -46,7 +54,12 @@ static inline void put_unaligned_le32(u32 val, void *p)
>
> static inline void put_unaligned_le64(u64 val, void *p)
> {
> - *((__le64 *)p) = cpu_to_le64(val);
> + if (BITS_PER_LONG == 64) {
> + *((__le64 *)p) = cpu_to_le64(val);
> + } else {
> + *((__le32 *)p) = cpu_to_le32(val);
> + *((__le32 *)p + 1) = cpu_to_le32(val >> 32);
> + }
> }
>
> static inline void put_unaligned_be16(u16 val, void *p)
> @@ -61,7 +74,12 @@ static inline void put_unaligned_be32(u32 val, void *p)
>
> static inline void put_unaligned_be64(u64 val, void *p)
> {
> - *((__be64 *)p) = cpu_to_be64(val);
> + if (BITS_PER_LONG == 64) {
> + *((__be64 *)p) = cpu_to_be64(val);
> + } else {
> + *((__be32 *)p) = cpu_to_le32(val >> 32);
be32
> + *((__be32 *)p + 1) = cpu_to_le32(val);
be32
Marc
--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de |
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next prev parent reply other threads:[~2016-03-04 11:19 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-03 22:27 DWord alignment on ARMv7 Marc Kleine-Budde
2016-03-03 23:54 ` Will Deacon
2016-03-04 8:01 ` btrfs_get_token_64() alignment problem on ARM (was: Re: DWord alignment on ARMv7) Marc Kleine-Budde
2016-03-04 9:16 ` David Sterba
2016-03-04 10:48 ` DWord alignment on ARMv7 Ard Biesheuvel
2016-03-04 11:02 ` Russell King - ARM Linux
2016-03-04 11:14 ` Ard Biesheuvel
2016-03-04 11:19 ` Marc Kleine-Budde [this message]
2016-03-04 11:26 ` Ard Biesheuvel
2016-03-04 11:38 ` Arnd Bergmann
2016-03-04 11:44 ` Ard Biesheuvel
2016-03-04 13:30 ` Arnd Bergmann
2016-03-04 13:33 ` Ard Biesheuvel
2016-03-04 13:46 ` Russell King - ARM Linux
2016-03-04 14:41 ` Arnd Bergmann
2016-03-04 14:56 ` Russell King - ARM Linux
2016-03-04 15:49 ` Arnd Bergmann
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